This invention relates in general to cattle stalls, e.g., milking parlors, and is more particularly directed to a front positioning rail for a diagonal milking parlor. The invention is more particularly concerned with an improved rail that assists the cows in self-positioning, and accommodates cows of various lengths. The invention is further concerned with a brisket rail which permits indexing, or bringing the rear legs of the cattle against the back wall or splash shield of the parlor, and which further moves or lifts away to permit the cows to exit the parlor after milking.
A milking parlor generally consists of an array of individual stalls, each being designed to hold a single cow as she is being milked. The cows are walked into the parlor through an entry gate, and then each cow is directed to her respective stall. There an attendant washes her udders, attaches a milking unit, monitors and attends to the milking operation, disconnects the milking unit, and releases the cows so another group of cows can be milked. In parlors of this type, the cows proceed in single file through the entry gate into the parlor, and can exit, either in the same fashion through an exit gate at the far end, or in gang fashion out the side of the parlor. There are various schemes for milking parlors, including herringbone, diagonal, and parallel or side-by-side. A parallel milking parlor operation is described in my earlier U.S. Pat. Nos. 5,230,299 and 5,285,746.
A relatively new design in milking parlors is a hybrid of the parallel and herringbone configurations. These parlors place the cows at an angle of 50 to 70 degrees relative to the curb line. In a conventional herringbone parlor, the cow is at 30 degrees to no more than 45 degrees to the curb line, with a spacing of between 36 inches and 44 inches between cows along the curb line. By contrast, the parallel or side-by-side parlor places the cows at 90 degrees, and at a spacing of 27 inches to 29 inches along the curb line, but requires the cows to be milked between their hind legs. In the hybrid diagonal design, the cows are placed at a typical angle of 50 to 60 degrees, with a spacing between cows of 30 inches. It is possible to achieve a steeper angle of 70 degrees and a spacing of only 27 inches along the curb. An example of an existing diagonal parlor design is the ParaBone.RTM. parlor, sold by Germania Dairy Automation, Inc. An example of brisket bar apparatus for aligning cows in both a herringbone and a diagonal parlor, and for releasing them after milking, is described in Reisgies et al. U.S. Pat. No. 4,951,608.
Sequencing gates, which are required in parallel or side-by-side parlors, are omitted in the diagonal parlor. This simplifies installation, and also aids in cow entry, as it creates a wider lane for the cows. However, as the angle of the parlor increases towards 90 degrees, the problem of cows turning around increases. At 90 degrees or other high angle, the cows can move left or right where there are no sequencing gates. In the standard parallel parlor, the sequencing gates serve the purposes of restricting cows to right angle positioning, and act as a barrier to cows moving away from their positions. On the other extreme, in the herringbone design, i.e., at angles of 30 degrees, the cows do not have space to turn around. However, as the angle increases, e.g., at 55 degrees to 70 degrees, cows have enough space to turn around if they are disturbed or "spooked."
Another shortcoming of the diagonal parlor--when a conventional front rail is used--is that of defining the proper milking or stall positioning for the cows. Where there is no definite position for the cow to take along the front positioning rail, overloading or underloading of the parlor frequently occurs. Cows can "bunch up" or fit loose along the rail. This is of course a problem because there are a given number of milking units, e.g., eight units, for a given parlor. Underloading means that the parlor is not used to capacity, and overloading means that at least one cow must be milked with a portable milking unit, which also decreases parlor efficiency. At the rear of the parlor, the splash or manure shield can be of a serpentine or S-shaped configuration, but this is on the side away from the cow's head. The cows cannot easily, and often do not follow the S configuration as to where they place their hind ends. Of course, where the parlor has a straight splash shield, there is nothing to define where the cow's hind end should be placed. Since the number of milking units and the automated equipment is fixed, and because these units are disposed at the rear of the stalls for a given number of cows and at a relatively fixed position, cows placed erratically in the parlor--or extra cows--present a hindrance to efficient milking.
A further shortcoming of the standard or conventional front rail is the manner that it indexes the cows, i.e., brings them to the proper milking position with their hind legs against the back rail or splash shield. Where the front rail is movable, the rail is in a forward position when the cows enter the parlor. After the cows have moved into the parlor, the front rail assembly can move back towards the cows, e.g., by air cylinder operation. This shortens the distance from the front rail to the rear splash shield. Cows can compensate for this in two ways, i.e., either by backing up against the splash shield (the desirable action) or by sliding forward along the front rail and changing angle (which is undesirable). When the cows only move along the from rail, the cows will be in a poorer milking position, that is, a worse position for access by the operator. In longer cows, some change of angle is acceptable as long as they have first moved their hind legs against the splash shield. This action actually provides the longer cow with more space and does not "trap" her in. Also, when the longer cows turn slightly, the front rail can continue to come back and index the shorter cows as well as the longer cows against the splash shield. In an ideal front positioning rail assembly, some limited sliding along the rail is desirable for the longer cows, but should be discouraged until the cows are all the way back against the splash shield.